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Care Guide

About Care Guides[x]
These care guides are written to help your clients understand common conditions, tests, and procedures, as well as to provide basic information about pet care. They are based on the most up-to-date, documented information, recommendations, and guidelines available in the United States at the time of writing. Pharmaceutical product licensing, availability, and usage recommendations are based on US product information. Use the Download Handout button to generate a PDF for printing or e-mailing to your clients.

Lice and Your Dog

Lice are uncommon parasites of pet dogs. Dogs kept in overcrowded or unsanitary conditions are at greater risk.

Dog lice don’t infest people, but they can spread among other dogs.

Your veterinarian can recommend safe and effective products to help protect your dog from lice.

What Are Lice?

Lice are small, wingless, parasitic insects. They can infest a variety of hosts, including cats, birds, horses, dogs, and people. However, lice are host-specific, which means that the species of lice that infest humans (for example) don’t infest other animals.

Lice are uncommon in pet dogs, but two species of lice can infest dogs. Trichodectes canis is a biting louse that grasps the host dog’s hair and eats skin debris and secretions. Linognathus setosus is a bloodsucking louse that similarly attaches to its host’s hair; it uses its mouthparts to pierce the skin and drink blood.

A louse spends its entire life on its host. Adult lice attach to the host and feed. When they reproduce, the female lice lay eggs (called “nits”) that remain attached to the host’s hairs until they hatch, about 7 to 14 days later. After a few developmental stages, adult lice emerge to continue the cycle. The entire life cycle takes about 3 to 6 weeks to complete.

Why Are Lice a Problem for Dogs?

The clinical signs associated with lice can vary in severity and may be limited to skin problems such as the following:

Skin irritation

Itching and restlessness

Hair loss

Skin wounds (from scratching and biting)

However, if a dog is heavily infested with bloodsucking lice, the parasites can drink enough blood to cause anemia (an inadequate number of red blood cells) from blood loss. One type of louse that infests dogs can help transmit tapeworms (Dipylidium caninum) if an infected louse is eaten during grooming.

How Do Dogs Get Lice?

Dogs most commonly get lice from being in contact with other dogs that are infested. Dogs that live together, play together, or groom each other can spread the parasites to each other. Lice can also be transmitted by “fomites.” Fomites are objects such as combs, brushes, or blankets that, if shared, can help spread lice from pet to pet. Lice can only live in the environment for a very short time (hours to days), so transmission generally occurs from direct contact between dogs.

Despite a popular myth, dogs can’t get lice from people, and people can’t be infested from exposure to a dog with lice. The species of lice that infest dogs, cats, and humans are different, so if a child gets head lice, don’t blame the dog!

Lice are very uncommon in pet dogs that are in good health and kept under reasonably clean conditions. However, dogs that are very young, elderly, sick, malnourished, and/or housed in overcrowded or unsanitary conditions are more likely to have a problem with lice.

How Are Lice Diagnosed and Treated?

Veterinarians generally diagnose lice infestation based on clinical signs and finding evidence of lice on the dog. Your veterinarian may pluck a few hairs from your pet and look at the sample under the microscope to identify lice or nits clinging to the hairs. Sometimes, lice can also be seen on the pet by looking closely at the skin and hair with a magnifying glass.

Fortunately, there are many products that safely and effectively treat lice. There are many options, so ask your veterinarian about the best choice for your dog. Even some of the monthly spot-on flea products are effective against lice. However, most dogs infested with lice are living under unsanitary conditions, so this should also be addressed if the problem is to be resolved completely. The dog’s living area should be thoroughly cleaned, and any blankets, brushes, combs, or other fomites should be washed.

Severely infested dogs that are anemic may need hospitalization for blood transfusions and intensive care. Dogs that are severely malnourished or otherwise ill may also need hospitalization. For most dogs, however, treatment can take place at home.

How Can I Protect My Dog From Lice?

Regular use of certain monthly spot-on flea control products can protect your dog if he or she is exposed to lice. However, reducing exposure risk is highly recommended. Any new pets being introduced into the home should be examined by a veterinarian to be sure they are not bringing lice or any other parasites or illnesses into the house. A precautionary quarantine period may be advised.

If one dog in the house is being treated for lice, your veterinarian may recommend treating other household dogs at the same time because the parasites are easily transmitted from dog to dog.

Pets that are being treated for lice should be separated from other pets until the problem has been resolved. Because some products are not effective against nits, treatment may need to be repeated in a week or two to target lice that were nits at the time of initial treatment. Depending on which product is used, your veterinarian can advise you about the treatment schedule and when it is safe to expose your treated dog to other dogs.

Fortunately, lice are host-specific. Children or other family members are not at risk if your dog has lice.